diff --git a/homeassistant/components/almond/__init__.py b/homeassistant/components/almond/__init__.py
index 8877107b984..c9870b4cd32 100644
--- a/homeassistant/components/almond/__init__.py
+++ b/homeassistant/components/almond/__init__.py
@@ -286,9 +286,9 @@ class AlmondAgent(conversation.AbstractConversationAgent):
         buffer = ""
         for message in response["messages"]:
             if message["type"] == "text":
-                buffer += "\n" + message["text"]
+                buffer += f"\n{message['text']}"
             elif message["type"] == "picture":
-                buffer += "\n Picture: " + message["url"]
+                buffer += f"\n Picture: {message['url']}"
             elif message["type"] == "rdl":
                 buffer += (
                     "\n Link: "
diff --git a/homeassistant/components/anthemav/media_player.py b/homeassistant/components/anthemav/media_player.py
index b7df82961c7..9a64b56b575 100644
--- a/homeassistant/components/anthemav/media_player.py
+++ b/homeassistant/components/anthemav/media_player.py
@@ -186,4 +186,5 @@ class AnthemAVR(MediaPlayerDevice):
     def dump_avrdata(self):
         """Return state of avr object for debugging forensics."""
         attrs = vars(self)
-        return "dump_avrdata: " + ", ".join("%s: %s" % item for item in attrs.items())
+        items_string = ", ".join(f"{item}: {item}" for item in attrs.items())
+        return f"dump_avrdata: {items_string}"
diff --git a/homeassistant/components/apple_tv/__init__.py b/homeassistant/components/apple_tv/__init__.py
index 52e02cfaf72..aae4165fe5f 100644
--- a/homeassistant/components/apple_tv/__init__.py
+++ b/homeassistant/components/apple_tv/__init__.py
@@ -129,8 +129,10 @@ async def scan_apple_tvs(hass):
     if not devices:
         devices = ["No device(s) found"]
 
+    found_devices = "<br /><br />".join(devices)
+
     hass.components.persistent_notification.async_create(
-        "The following devices were found:<br /><br />" + "<br /><br />".join(devices),
+        f"The following devices were found:<br /><br />{found_devices}",
         title=NOTIFICATION_SCAN_TITLE,
         notification_id=NOTIFICATION_SCAN_ID,
     )
diff --git a/homeassistant/components/bluesound/media_player.py b/homeassistant/components/bluesound/media_player.py
index 300927abefa..86e62adc618 100644
--- a/homeassistant/components/bluesound/media_player.py
+++ b/homeassistant/components/bluesound/media_player.py
@@ -1038,9 +1038,7 @@ class BluesoundPlayer(MediaPlayerDevice):
             volume = 0
         elif volume > 1:
             volume = 1
-        return await self.send_bluesound_command(
-            "Volume?level=" + str(float(volume) * 100)
-        )
+        return await self.send_bluesound_command(f"Volume?level={float(volume) * 100}")
 
     async def async_mute_volume(self, mute):
         """Send mute command to media player."""
@@ -1050,5 +1048,5 @@ class BluesoundPlayer(MediaPlayerDevice):
                 self._lastvol = volume
             return await self.send_bluesound_command("Volume?level=0")
         return await self.send_bluesound_command(
-            "Volume?level=" + str(float(self._lastvol) * 100)
+            f"Volume?level={float(self._lastvol) * 100}"
         )
diff --git a/homeassistant/components/denon/media_player.py b/homeassistant/components/denon/media_player.py
index cd9d6e8feb7..9f210add0af 100644
--- a/homeassistant/components/denon/media_player.py
+++ b/homeassistant/components/denon/media_player.py
@@ -257,11 +257,12 @@ class DenonDevice(MediaPlayerDevice):
 
     def set_volume_level(self, volume):
         """Set volume level, range 0..1."""
-        self.telnet_command("MV" + str(round(volume * self._volume_max)).zfill(2))
+        self.telnet_command(f"MV{str(round(volume * self._volume_max)).zfill(2)}")
 
     def mute_volume(self, mute):
         """Mute (true) or unmute (false) media player."""
-        self.telnet_command("MU" + ("ON" if mute else "OFF"))
+        mute_status = "ON" if mute else "OFF"
+        self.telnet_command(f"MU{mute_status})")
 
     def media_play(self):
         """Play media player."""
@@ -289,4 +290,4 @@ class DenonDevice(MediaPlayerDevice):
 
     def select_source(self, source):
         """Select input source."""
-        self.telnet_command("SI" + self._source_list.get(source))
+        self.telnet_command(f"SI{self._source_list.get(source)}")
diff --git a/homeassistant/components/entur_public_transport/sensor.py b/homeassistant/components/entur_public_transport/sensor.py
index 0425accd06b..19510337d6a 100644
--- a/homeassistant/components/entur_public_transport/sensor.py
+++ b/homeassistant/components/entur_public_transport/sensor.py
@@ -241,7 +241,7 @@ class EnturPublicTransportSensor(Entity):
             return
 
         for i, call in enumerate(calls[2:]):
-            key_name = "departure_#" + str(i + 3)
+            key_name = f"departure_#{i + 3}"
             self._attributes[key_name] = (
                 f"{'' if bool(call.is_realtime) else 'ca. '}"
                 f"{call.expected_departure_time.strftime('%H:%M')} {call.front_display}"
diff --git a/homeassistant/components/itunes/media_player.py b/homeassistant/components/itunes/media_player.py
index 327cbf5e9ac..ccefb681d6e 100644
--- a/homeassistant/components/itunes/media_player.py
+++ b/homeassistant/components/itunes/media_player.py
@@ -163,7 +163,7 @@ class Itunes:
 
         if found_playlists:
             playlist = found_playlists[0]
-            path = "/playlists/" + playlist["id"] + "/play"
+            path = f"/playlists/{playlist['id']}/play"
             return self._request("PUT", path)
 
     def artwork_url(self):
@@ -324,7 +324,7 @@ class ItunesDevice(MediaPlayerDevice):
             self.player_state in (STATE_PLAYING, STATE_IDLE, STATE_PAUSED)
             and self.current_title is not None
         ):
-            return self.client.artwork_url() + "?id=" + self.content_id
+            return f"{self.client.artwork_url()}?id={self.content_id}"
 
         return (
             "https://cloud.githubusercontent.com/assets/260/9829355"
diff --git a/homeassistant/components/life360/device_tracker.py b/homeassistant/components/life360/device_tracker.py
index b6cd67c2627..5403a483ffb 100644
--- a/homeassistant/components/life360/device_tracker.py
+++ b/homeassistant/components/life360/device_tracker.py
@@ -214,7 +214,7 @@ class Life360Scanner:
             err_msg = member["issues"]["title"]
             if err_msg:
                 if member["issues"]["dialog"]:
-                    err_msg += ": " + member["issues"]["dialog"]
+                    err_msg += f": {member['issues']['dialog']}"
             else:
                 err_msg = "Location information missing"
             self._err(dev_id, err_msg)
diff --git a/homeassistant/components/linky/sensor.py b/homeassistant/components/linky/sensor.py
index 846b7eeb99f..7e9da01eb9a 100644
--- a/homeassistant/components/linky/sensor.py
+++ b/homeassistant/components/linky/sensor.py
@@ -159,4 +159,4 @@ class LinkySensor(Entity):
             year_index = INDEX_CURRENT
             if self._time.endswith("Dec"):
                 year_index = INDEX_LAST
-            self._time += " " + self._account.data[YEARLY][year_index][TIME]
+            self._time += f" {self._account.data[YEARLY][year_index][TIME]}"
diff --git a/homeassistant/components/london_air/sensor.py b/homeassistant/components/london_air/sensor.py
index 77af10928dc..7eb410cacab 100644
--- a/homeassistant/components/london_air/sensor.py
+++ b/homeassistant/components/london_air/sensor.py
@@ -157,9 +157,9 @@ def parse_species(species_data):
             species_dict["code"] = species["@SpeciesCode"]
             species_dict["quality"] = species["@AirQualityBand"]
             species_dict["index"] = species["@AirQualityIndex"]
-            species_dict["summary"] = (
-                species_dict["code"] + " is " + species_dict["quality"]
-            )
+            species_dict[
+                "summary"
+            ] = f"{species_dict['code']} is {species_dict['quality']}"
             parsed_species_data.append(species_dict)
             quality_list.append(species_dict["quality"])
     return parsed_species_data, quality_list
diff --git a/homeassistant/components/modbus/sensor.py b/homeassistant/components/modbus/sensor.py
index 8c2b950648b..59abe2fd6d5 100644
--- a/homeassistant/components/modbus/sensor.py
+++ b/homeassistant/components/modbus/sensor.py
@@ -246,7 +246,7 @@ class ModbusRegisterSensor(RestoreEntity):
         if isinstance(val, int):
             self._value = str(val)
             if self._precision > 0:
-                self._value += "." + "0" * self._precision
+                self._value += f".{'0' * self._precision}"
         else:
             self._value = f"{val:.{self._precision}f}"
 
diff --git a/homeassistant/components/neato/vacuum.py b/homeassistant/components/neato/vacuum.py
index adff293301b..7a9cd1d9e45 100644
--- a/homeassistant/components/neato/vacuum.py
+++ b/homeassistant/components/neato/vacuum.py
@@ -208,7 +208,7 @@ class NeatoConnectedVacuum(StateVacuumDevice):
                     and "name" in self._state["cleaning"]["boundary"]
                 ):
                     self._status_state += (
-                        " " + self._state["cleaning"]["boundary"]["name"]
+                        f" {self._state['cleaning']['boundary']['name']}"
                     )
             else:
                 self._status_state = robot_alert
diff --git a/homeassistant/components/onewire/sensor.py b/homeassistant/components/onewire/sensor.py
index da8b1ed359b..90d943dd755 100644
--- a/homeassistant/components/onewire/sensor.py
+++ b/homeassistant/components/onewire/sensor.py
@@ -210,7 +210,7 @@ class OneWire(Entity):
 
     def __init__(self, name, device_file, sensor_type):
         """Initialize the sensor."""
-        self._name = name + " " + sensor_type.capitalize()
+        self._name = f"{name} {sensor_type.capitalize()}"
         self._device_file = device_file
         self._unit_of_measurement = SENSOR_TYPES[sensor_type][1]
         self._state = None
diff --git a/homeassistant/components/pioneer/media_player.py b/homeassistant/components/pioneer/media_player.py
index 66e57d156ef..6e902271171 100644
--- a/homeassistant/components/pioneer/media_player.py
+++ b/homeassistant/components/pioneer/media_player.py
@@ -142,7 +142,7 @@ class PioneerDevice(MediaPlayerDevice):
         # Build the source name dictionaries if necessary
         if not self._source_name_to_number:
             for i in range(MAX_SOURCE_NUMBERS):
-                result = self.telnet_request(telnet, "?RGB" + str(i).zfill(2), "RGB")
+                result = self.telnet_request(telnet, f"?RGB{str(i).zfill(2)}", "RGB")
 
                 if not result:
                     continue
diff --git a/homeassistant/components/raspihats/switch.py b/homeassistant/components/raspihats/switch.py
index 8a083dbe2c9..d6129577118 100644
--- a/homeassistant/components/raspihats/switch.py
+++ b/homeassistant/components/raspihats/switch.py
@@ -106,8 +106,8 @@ class I2CHatSwitch(ToggleEntity):
     def _log_message(self, message):
         """Create log message."""
         string = self._name + " "
-        string += self._board + "I2CHat@" + hex(self._address) + " "
-        string += "channel:" + str(self._channel) + message
+        string += f"{self._board}I2CHat@{hex(self._address)} "
+        string += f"channel:{str(self._channel)}{message}"
         return string
 
     @property
diff --git a/homeassistant/components/rfxtrx/sensor.py b/homeassistant/components/rfxtrx/sensor.py
index 3f74ff18695..759268140fc 100644
--- a/homeassistant/components/rfxtrx/sensor.py
+++ b/homeassistant/components/rfxtrx/sensor.py
@@ -76,7 +76,7 @@ def setup_platform(hass, config, add_entities, discovery_info=None):
         if not isinstance(event, SensorEvent):
             return
 
-        device_id = "sensor_" + slugify(event.device.id_string.lower())
+        device_id = f"sensor_{slugify(event.device.id_string.lower())}"
 
         if device_id in RFX_DEVICES:
             sensors = RFX_DEVICES[device_id]
diff --git a/homeassistant/components/thinkingcleaner/switch.py b/homeassistant/components/thinkingcleaner/switch.py
index 172951ed1ef..6ef1a6f9556 100644
--- a/homeassistant/components/thinkingcleaner/switch.py
+++ b/homeassistant/components/thinkingcleaner/switch.py
@@ -98,7 +98,7 @@ class ThinkingCleanerSwitch(ToggleEntity):
     @property
     def name(self):
         """Return the name of the sensor."""
-        return self._tc_object.name + " " + SWITCH_TYPES[self.type][0]
+        return f"{self._tc_object.name} {SWITCH_TYPES[self.type][0]}"
 
     @property
     def is_on(self):
diff --git a/homeassistant/components/traccar/device_tracker.py b/homeassistant/components/traccar/device_tracker.py
index b6e829750e9..dc2b60dec1a 100644
--- a/homeassistant/components/traccar/device_tracker.py
+++ b/homeassistant/components/traccar/device_tracker.py
@@ -316,7 +316,7 @@ class TraccarScanner:
                     None,
                 )
                 self._hass.bus.async_fire(
-                    "traccar_" + self._event_types.get(event["type"]),
+                    f"traccar_{self._event_types.get(event['type'])}",
                     {
                         "device_traccar_id": event["deviceId"],
                         "device_name": device_name,
diff --git a/homeassistant/components/wink/__init__.py b/homeassistant/components/wink/__init__.py
index 53bac129dbc..54d3b2efde9 100644
--- a/homeassistant/components/wink/__init__.py
+++ b/homeassistant/components/wink/__init__.py
@@ -749,7 +749,7 @@ class WinkDevice(Entity):
                 self.schedule_update_ha_state()
         except (ValueError, KeyError, AttributeError):
             _LOGGER.error(
-                "Error in pubnub JSON for %s polling API for current state", self.name,
+                "Error in pubnub JSON for %s polling API for current state", self.name
             )
             self.schedule_update_ha_state(True)
 
@@ -912,7 +912,7 @@ class WinkNimbusDialDevice(WinkDevice):
     @property
     def name(self):
         """Return the name of the device."""
-        return self.parent.name() + " dial " + str(self.wink.index() + 1)
+        return f"{self.parent.name()} dial {self.wink.index() + 1}"
 
     @property
     def device_state_attributes(self):
diff --git a/homeassistant/components/wunderground/sensor.py b/homeassistant/components/wunderground/sensor.py
index de1e48c9c14..22aefa5be4a 100644
--- a/homeassistant/components/wunderground/sensor.py
+++ b/homeassistant/components/wunderground/sensor.py
@@ -329,7 +329,7 @@ class WUAlertsSensorConfig(WUSensorConfig):
             for alert in ALERTS_ATTRS:
                 if data[alert]:
                     if multiple_alerts:
-                        dkey = alert.capitalize() + "_" + data["type"]
+                        dkey = f"{alert.capitalize()}_{data['type']}"
                     else:
                         dkey = alert.capitalize()
                     attrs[dkey] = data[alert]
diff --git a/homeassistant/components/xiaomi_miio/remote.py b/homeassistant/components/xiaomi_miio/remote.py
index 9e4446f2964..8c4d68208b4 100644
--- a/homeassistant/components/xiaomi_miio/remote.py
+++ b/homeassistant/components/xiaomi_miio/remote.py
@@ -100,12 +100,12 @@ async def async_setup_platform(hass, config, async_add_entities, discovery_info=
     if DATA_KEY not in hass.data:
         hass.data[DATA_KEY] = {}
 
-    friendly_name = config.get(CONF_NAME, "xiaomi_miio_" + host.replace(".", "_"))
+    friendly_name = config.get(CONF_NAME, f"xiaomi_miio_{host.replace('.', '_')}")
     slot = config.get(CONF_SLOT)
     timeout = config.get(CONF_TIMEOUT)
 
     xiaomi_miio_remote = XiaomiMiioRemote(
-        friendly_name, device, unique_id, slot, timeout, config.get(CONF_COMMANDS),
+        friendly_name, device, unique_id, slot, timeout, config.get(CONF_COMMANDS)
     )
 
     hass.data[DATA_KEY][host] = xiaomi_miio_remote
diff --git a/homeassistant/components/yamaha/media_player.py b/homeassistant/components/yamaha/media_player.py
index 7ab7d5b3a47..5aa0299200a 100644
--- a/homeassistant/components/yamaha/media_player.py
+++ b/homeassistant/components/yamaha/media_player.py
@@ -233,7 +233,7 @@ class YamahaDevice(MediaPlayerDevice):
         zone_name = self._zone_names.get(self._zone, self._zone)
         if zone_name != "Main_Zone":
             # Zone will be one of Main_Zone, Zone_2, Zone_3
-            name += " " + zone_name.replace("_", " ")
+            name += f" {zone_name.replace('_', ' ')}"
         return name
 
     @property
diff --git a/homeassistant/components/zha/core/device.py b/homeassistant/components/zha/core/device.py
index 716ed5040ae..e0d9cfa0a3e 100644
--- a/homeassistant/components/zha/core/device.py
+++ b/homeassistant/components/zha/core/device.py
@@ -608,7 +608,7 @@ class ZHADevice(LogMixin):
                     cluster_binding.id,
                     group_id,
                 )
-                zdo.debug("processing " + op_msg, *op_params)
+                zdo.debug(f"processing {op_msg}", *op_params)
                 tasks.append(
                     (
                         zdo.request(
diff --git a/homeassistant/scripts/check_config.py b/homeassistant/scripts/check_config.py
index c5224f8f959..23d90796c86 100644
--- a/homeassistant/scripts/check_config.py
+++ b/homeassistant/scripts/check_config.py
@@ -186,7 +186,7 @@ def check(config_dir, secrets=False):
             continue
         # The * in the key is removed to find the mock_function (side_effect)
         # This allows us to use one side_effect to patch multiple locations
-        mock_function = locals()["mock_" + key.replace("*", "")]
+        mock_function = locals()[f"mock_{key.replace('*', '')}"]
         PATCHES[key] = patch(val[0], side_effect=mock_function)
 
     # Start all patches
diff --git a/script/hassfest/codeowners.py b/script/hassfest/codeowners.py
index 0a653ea0e90..0fdb8eafb0f 100644
--- a/script/hassfest/codeowners.py
+++ b/script/hassfest/codeowners.py
@@ -52,7 +52,7 @@ def generate_and_validate(integrations: Dict[str, Integration]):
             "homeassistant/components/{}/* {}".format(domain, " ".join(codeowners))
         )
 
-    parts.append("\n" + INDIVIDUAL_FILES.strip())
+    parts.append(f"\n{INDIVIDUAL_FILES.strip()}")
 
     return "\n".join(parts)
 
diff --git a/script/inspect_schemas.py b/script/inspect_schemas.py
index 91a54f87f9e..6ea37f26d10 100755
--- a/script/inspect_schemas.py
+++ b/script/inspect_schemas.py
@@ -52,7 +52,7 @@ def main():
 
         add_msg(
             f"CONFIG_SCHEMA {schema_type}",
-            module_name + " " + color("cyan", str(schema)[:60]),
+            f"{module_name} {color('cyan', str(schema)[:60])}",
         )
 
     for key in sorted(msg):
diff --git a/tests/components/smartthings/conftest.py b/tests/components/smartthings/conftest.py
index 0dc71ea72b9..e05917c17d8 100644
--- a/tests/components/smartthings/conftest.py
+++ b/tests/components/smartthings/conftest.py
@@ -105,7 +105,7 @@ def app_fixture(hass, config_file):
     app.app_type = "WEBHOOK_SMART_APP"
     app.classifications = [CLASSIFICATION_AUTOMATION]
     app.display_name = "Home Assistant"
-    app.description = hass.config.location_name + " at " + hass.config.api.base_url
+    app.description = f"{hass.config.location_name} at {hass.config.api.base_url}"
     app.single_instance = True
     app.webhook_target_url = webhook.async_generate_url(
         hass, hass.data[DOMAIN][CONF_WEBHOOK_ID]
diff --git a/tests/components/zha/common.py b/tests/components/zha/common.py
index 2f0966ae739..2542037a2bf 100644
--- a/tests/components/zha/common.py
+++ b/tests/components/zha/common.py
@@ -146,7 +146,7 @@ async def find_entity_id(domain, zha_device, hass):
     machine so that we can test state changes.
     """
     ieeetail = "".join([f"{o:02x}" for o in zha_device.ieee[:4]])
-    head = f"{domain}." + slugify(f"{zha_device.name} {ieeetail}")
+    head = f"{domain}.{slugify(f'{zha_device.name} {ieeetail}')}"
 
     enitiy_ids = hass.states.async_entity_ids(domain)
     await hass.async_block_till_done()